Zachary Anderson
d0295c873c
Fuchsia requires the ability to sandbox Isolates w.r.t. file IO. When a new Isolate starts, Fuchsia will pass the Isolate an object called a namespace. We can translate the namespace object into a file descriptor suitable for passing to the *at() family of POSIX file system calls. The file system calls will then have visibility only into the specified namespace. We also plumb Namespaces through on all the other platforms as well to make the change easier to test and so that in the future we can implement e.g. per-isolate cwds. This change adds a new internal class to dart:io called _Namespace, which is implemented in a patch file. See: sdk/lib/io/namespace_impl.dart runtime/bin/namespace_patch.dart The embedder can set up a non-default namespace by calling _Namespace._setupNamespace during Isolate setup. Instances of _Namespace have a native field that holds a pointer to a native Namespace object. See: runtime/bin/namespace.h Calls from e.g. file_impl.dart are now also passed a _Namespace object. The implementations in e.g. file.cc and file_linux.cc then extract the namespace, and use it to compute a file descriptor and path suitable for passing to e.g. openat(). related US-313 R=asiva@google.com, rmacnak@google.com Review-Url: https://codereview.chromium.org/3007703002 .
104 lines
2.7 KiB
C++
104 lines
2.7 KiB
C++
// Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file
|
|
// for details. All rights reserved. Use of this source code is governed by a
|
|
// BSD-style license that can be found in the LICENSE file.
|
|
|
|
#include "platform/globals.h"
|
|
#if defined(HOST_OS_ANDROID)
|
|
|
|
#include "bin/namespace.h"
|
|
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
|
|
#include "bin/fdutils.h"
|
|
#include "bin/file.h"
|
|
#include "platform/signal_blocker.h"
|
|
|
|
namespace dart {
|
|
namespace bin {
|
|
|
|
Namespace* Namespace::Create(const char* path) {
|
|
const intptr_t fd = TEMP_FAILURE_RETRY(open(path, O_RDONLY));
|
|
if (fd < 0) {
|
|
return NULL;
|
|
}
|
|
return new Namespace(fd);
|
|
}
|
|
|
|
Namespace::~Namespace() {
|
|
if (namespc_ != kNone) {
|
|
VOID_TEMP_FAILURE_RETRY(close(namespc_));
|
|
}
|
|
}
|
|
|
|
intptr_t Namespace::Default() {
|
|
return kNone;
|
|
}
|
|
|
|
const char* Namespace::GetCurrent(Namespace* namespc) {
|
|
if ((namespc == NULL) || (namespc->namespc() == kNone)) {
|
|
// TODO(zra): When there are isolate-specific namespaces, extract it from
|
|
// the namespace instead of calling getcwd.
|
|
char buffer[PATH_MAX];
|
|
if (getcwd(buffer, PATH_MAX) == NULL) {
|
|
return NULL;
|
|
}
|
|
return DartUtils::ScopedCopyCString(buffer);
|
|
}
|
|
|
|
// TODO(zra): Allow changing the current working directory when there is
|
|
// a non-default namespace.
|
|
return DartUtils::ScopedCopyCString("/");
|
|
}
|
|
|
|
bool Namespace::SetCurrent(Namespace* namespc, const char* path) {
|
|
if ((namespc == NULL) || (namespc->namespc() == kNone)) {
|
|
return (NO_RETRY_EXPECTED(chdir(path)) == 0);
|
|
}
|
|
|
|
// TODO(zra): If a non-default namespace is set up, changing the current
|
|
// working directoy is disallowed. We should relax this restriction when
|
|
// isolate-specific cwds are implemented.
|
|
errno = ENOSYS;
|
|
return false;
|
|
}
|
|
|
|
bool Namespace::ResolvePath(Namespace* namespc,
|
|
const char* path,
|
|
intptr_t* dirfd,
|
|
const char** resolved_path) {
|
|
ASSERT(dirfd != NULL);
|
|
ASSERT(resolved_path != NULL);
|
|
if ((namespc == NULL) || (namespc->namespc() == kNone)) {
|
|
*dirfd = AT_FDCWD;
|
|
*resolved_path = path;
|
|
return false;
|
|
}
|
|
*dirfd = namespc->namespc();
|
|
if (File::IsAbsolutePath(path)) {
|
|
if (strcmp(path, File::PathSeparator()) == 0) {
|
|
*resolved_path = ".";
|
|
} else {
|
|
*resolved_path = &path[1];
|
|
}
|
|
} else {
|
|
*resolved_path = path;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
NamespaceScope::NamespaceScope(Namespace* namespc, const char* path) {
|
|
owns_fd_ = Namespace::ResolvePath(namespc, path, &fd_, &path_);
|
|
}
|
|
|
|
NamespaceScope::~NamespaceScope() {
|
|
if (owns_fd_) {
|
|
FDUtils::SaveErrorAndClose(fd_);
|
|
}
|
|
}
|
|
|
|
} // namespace bin
|
|
} // namespace dart
|
|
|
|
#endif // defined(HOST_OS_ANDROID)
|